This proposal requests funding for the purchase of a rotating anode X-ray generator which would be used as the source of high intensity X-rays for one of the current diffractometers. This would enable routine structure determination on crystals considerably smaller than those that can presently be studied. Compounds for which suitable crystals cannot presently be obtained could be analyzed. The integrated major users group consists of NIH funded faculty in the Department of Chemistry, School of Science and the Department of Medicinal Chemistry, School of Pharmacy.